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What to look at on a car that hit a curb

Posted: Wed Sep 14, 2011 1:04 am
by wkohler
Let's say someone is driving an E12 and they hit a curb with the right front wheel (and the right rear, though not as bad in the rear). They're looking at the car and the wheel is toed out quite a bit while the left front is straight ahead and it's shifted back a bit in the wheel well - no impact on the firewall, etc, though there is evidence of the tread rubbing.

I wasn't driving the car when this happened five years ago, but now it's my problem to fix. :lol:

Basically, I'm interested in where to start looking and what pieces are the weakest in the setup. I've already decided the car needs to see a frame machine.

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Posted: Wed Sep 14, 2011 2:02 pm
by T.Hanson
I guess I'd look at the strut(s), tops where the bolts, nuts are exposed under the hood for bent, cracked metal around them. Inside fender wells, same thing.

After that: Strut integrity, axles, pitman arms, tie rods and center links straight. Mostly common sense, eyeballing the parts most likely to have been mechanically linked to the wheel.

Maybe pull the trunk pad and look for cracks around the top center area where the differential bolts to the mount underneath.

If the wheels were not seriously knocked off or bent, wild guess the under carriage wasn't either. Unless it's doing the Hula and you have to hold the wheel left to go straight.

Re: What to look at on a car that hit a curb

Posted: Wed Sep 14, 2011 2:11 pm
by Blaise
wkohler wrote:Let's say someone is driving an E12 and they hit a curb with the right front wheel (and the right rear, though not as bad in the rear). They're looking at the car and the wheel is toed out quite a bit while the left front is straight ahead and it's shifted back a bit in the wheel well - no impact on the firewall, etc, though there is evidence of the tread rubbing.

I wasn't driving the car when this happened five years ago, but now it's my problem to fix. :lol:

Basically, I'm interested in where to start looking and what pieces are the weakest in the setup. I've already decided the car needs to see a frame machine.

Image
Check the frame rails in the engine bay. BTW, I have a spare complete front sub-frame.

Posted: Wed Sep 14, 2011 4:50 pm
by wkohler
Basically, I've been through the body pretty thoroughly from the top. I know that the front of the car needs help period from a previous accident and some rust (most-likely stemming from poor repair of said accident), but what I'm concerned about at this time is front suspension. The hat on the strut tower does have a slight bit of fatigue (cracked paint, one stud in the mount is kinda wonky). The lower aspect of the suspension (control arm, etc) is what I'm concerned about. Haven't had a chance to get under there yet (and won't for a couple weeks), but just curious about what I should look at first suspension-wise. Not terribly familiar with the components of the early front suspensions. I know on E28s, I'd be replacing the subframe.

Both wheels were pretty well trashed, though the rear not as much as the front, so the rear doesn't appear to be a concern at this time. The front is the largest concern.

Posted: Wed Sep 14, 2011 5:19 pm
by Blaise
My car had suffered similar damage. None of the exterior body work had been touched, but there must have been a hit to the front left wheel.

As a result, the frame rail was slightly crumbled just behind the sub-frame, the top of the strut tower had a small crack in it and the inner fender was not longer straight. The left front wheel rubbed at the back of the inner fender on full tilt turns. The steering column also did not align to the middle of firewall hole. All of this was actually subtle enough not to notice until you looked carefully and compared to the other side. My guess is that the subframe and suspension had been replaced, so I was not able to find any damage there.

I recently went through a sub-frame. You will find that they are rather simple and if something is bent, you should see it by comparing both sides.

The factory manual also has all of the frame alignment measurements in it. This is what I provided to the frame man who fixed it all. It is all straight and beautiful now.

Posted: Wed Sep 14, 2011 10:55 pm
by Mike W.
Seems like outside of the upper strut mounts, everything bolts to the subframe, unlike E28s that have the UCA bolting to the body. Take a tape to the subframe to crosscheck for straightness, eyeball the control arms and give the strut housing/spindle a good eye over, they can bend. And or the body/frame horns. Again, cross measure.